In the Dark? Rule Sets

This time "In the Dark?" describes the various rule sets that are in use
around the world. The series "Get Strong at Scoring" that ran in
the Journal looked at some of the counting methods in use. More
details of each rule set can be found in the book "Go Player's Almanac
2001".

Chinese rules, because of the game's origin, are the oldest; they are
area-counting rules. That is stones and territory are counted and you
simply need over half the board. Prisoners are not needed and are thrown
back in to the supply of unplayed stones. Seki is scored, with neutral
points shared. Counting is usually done by rearranging stones and
territories. Originally under Chinese rules it was the person who could
legally put the most stones on the board who won, but not filling each
group's two eyes was effectively a group tax.

Japanese rules are the most commonly used in the west and are normally
used in all BGA events (subject to their interpretation by the referee).
They were formalised in 1949 and have periodic revisions (such as that
in 1989). They are territory rules where only empty spaces and prisoners
count towards the score. They are defined in three parts: rules,
commentary and examples. The examples contain judgements on many
strange and unusual positions such as triple kos and round-robin kos.

The New Zealand players, being on the edge of the Go universe, devised
their own set of rules which are very short with some explicitly
recursive definitions. They are area-counting rules, but instead
of rearranging stones and territories to count the score as in
Chinese, players count the score point by point without any rearranging.

The Ing SST Rules of Goe were derived in 1975 by Mr Ing Chang-Ki,
president of a large computer company. They have been officially
used in Taiwan since 1977 and are used in various Ing-sponsored
events around the world. A fund was set up to promote the rules
worldwide which continues to support Goe in Europe and America.
The principle is area counting (SST is Stones and Spaces are Territory)
but play uses exactly 180 stones of each colour held in special Ing
measuring bowls. If you can fill in your own territory at the end
with unplayed stones and have some space left over, then you have
won. Unfortunately the rules have very complicated (or badly
described) ko rules to avoid special positions.

The American Go Association (AGA) adopted its own rules in 1991.
They are designed so that area counting and territory counting
give exactly the same result (except in a few special positions);
players can choose which way to count. To this end white must play
last, pass stones are given and territory is counted in seki.

From 2005 an International Rules Commission has been working to
try to find a ruleset suitable for all international events.